/// @tags:
#include <cstdio>
#include <functional>
#include <iostream>
#include <numeric>

using std::cin, std::cout, std::endl;

namespace BlueQuantum {

constexpr int maxn = 100;

int main() {
  int a, b;
  cin >> a >> b;
  if (a > b) {
    std::swap(a, b);
  }
  if (a * 2 == b || a * 2 + 1 == b) {
    cout << "Yes\n";
  } else {
    cout << "No\n";
  }
  return 0;
}

}  // namespace BlueQuantum

int main() {
#ifndef ONLINE_JUDGE
#ifdef LOCAL
  freopen("/tmp/CodeTmp/testdata.in", "r", stdin);
  freopen("/tmp/CodeTmp/testdata.out", "w", stdout);
#else
  freopen("A - Edge Checker 2.in", "r", stdin);
  freopen("A - Edge Checker 2.out", "w", stdout);
#endif
#endif

  std::ios::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL);
  return BlueQuantum::main();
}
